Dual-energy X-ray absorptiometry for measuring total bone mineral content in the rat: study of accuracy and precision

Sequential studies of osteopenic bone disease in small animals require the availability of non-invasive, accurate and precise methods to assess bone mineral content (BMC) and bone mineral density (BMD). Dual-energy X-ray absorptiometry (DXA), which is currently used in humans for this purpose, can also be applied to small animals by means of adapted software. Precision and accuracy of DXA was evaluated in 10 rats weighing 50-265 g. The rats were anesthetized with a mixture of ketamine-xylazine administrated intraperitoneally. Each rat was scanned six times consecutively in the antero-posterior incidence after repositioning using the rat whole-body software for determination of whole-body BMC and BMD (Hologic QDR 1000, software version 5.52). Scan duration was 10-20 min depending on rat size. After the last measurement, rats were sacrificed and soft tissues were removed by dermestid beetles. Skeletons were then scanned in vitro (ultra high resolution software, version 4.47). Bones were subsequently ashed and dissolved in hydrochloric acid and total body calcium directly assayed by atomic absorption spectrophotometry (TBCa[chem]). Total body calcium was also calculated from the DXA whole-body in vivo measurement (TBCa[DXA]) and from the ultra high resolution measurement (TBCa[UH]) under the assumption that calcium accounts for 40.5% of the BMC expressed as hydroxyapatite. Precision error for whole-body BMC and BMD (mean +/- S.D.) was 1.3% and 1.5%, respectively. Simple regression analysis between TBCa[DXA] or TBCa[UH] and TBCa[chem] revealed tight correlations (n = 0.991 and 0.996, respectively), with slopes and intercepts which were significantly different from 1 and 0, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

The EG95 antigen of Echinococcus spp. contains positively selected amino acids, which may influence host specificity and vaccine efficacy

Echinococcosis is a worldwide zoonotic parasitic disease of humans and various herbivorous domestic animals (intermediate hosts) transmitted by the contact with wild and domestic carnivores (definitive hosts), mainly foxes and dogs. Recently, a vaccine was developed showing high levels of protection against one parasite haplotype (G1) of Echinococcus granulosus, and its potential efficacy against distinct parasite variants or species is still unclear. Interestingly, the EG95 vaccine antigen is a secreted glycosylphosphatydilinositol (GPI)-anchored protein containing a fibronectin type III domain, which is ubiquitous in modular proteins involved in cell adhesion. EG95 is highly expressed in oncospheres, the parasite life cycle stage which actively invades the intermediate hosts. After amplifying and sequencing the complete CDS of 57 Echinococcus isolates belonging to 7 distinct species, we uncovered a large amount of genetic variability, which may influence protein folding. Two positively selected sites are outside the vaccine epitopes, but are predicted to alter protein conformation. Moreover, phylogenetic analyses indicate that EG95 isoform evolution is convergent with regard to the number of beta-sheets and alpha-helices. We conclude that having a variety of EG95 isoforms is adaptive for Echinococcus parasites, in terms of their ability to invade different hosts, and we propose that a mixture of isoforms could possibly maximize vaccine efficacy.

Light curing through glass ceramics: effect of curing mode on micromechanical properties of dual-curing resin cements

OBJECTIVES The aim of this study was to investigate micromechanical properties of five dual-curing resin cements after different curing modes including light curing through glass ceramic materials. MATERIALS AND METHODS Vickers hardness (VH) and indentation modulus (Y HU) of Panavia F2.0, RelyX Unicem 2 Automix, SpeedCEM, BisCem, and BeautiCem SA were measured after 1 week of storage (37 °C, 100 % humidity). The resin cements were tested following self-curing or light curing with the second-generation light-emitting diode (LED) curing unit Elipar FreeLight 2 in Standard Mode (1,545 mW/cm(2)) or with the third-generation LED curing unit VALO in High Power Mode (1,869 mW/cm(2)) or in XtraPower Mode (3,505 mW/cm(2)). Light curing was performed directly or through glass ceramic discs of 1.5 or 3 mm thickness of IPS Empress CAD or IPS e.max CAD. VH and Y HU were analysed with Kruskal-Wallis tests followed by pairwise Wilcoxon rank sum tests (α = 0.05). RESULTS RelyX Unicem 2 Automix resulted in the highest VH and Y HU followed by BeautiCem SA, BisCem, SpeedCEM, and finally Panavia F2.0. Self-curing of RelyX Unicem 2 Automix and SpeedCEM lowered VH and Y HU compared to light curing whereas self-curing of Panavia F2.0, BisCem, and BeautiCem SA led to similar or significantly higher VH and Y HU compared to light curing. Generally, direct light curing resulted in similar or lower VH and Y HU compared to light curing through 1.5-mm-thick ceramic discs. Light curing through 3-mm-thick discs of IPS e.max CAD generally reduced VH and Y HU for all resin cements except SpeedCEM, which was the least affected by light curing through ceramic discs. CONCLUSIONS The resin cements responded heterogeneously to changes in curing mode. The applied irradiances and light curing times adequately cured the resin cements even through 1.5-mm-thick ceramic discs. CLINICAL RELEVANCE When light curing resin cements through thick glass ceramic restorations, clinicians should consider to prolong the light curing times even with LED curing units providing high irradiances.

Light curing through glass ceramics with a second- and a third-generation LED curing unit: effect of curing mode on the degree of conversion of dual-curing resin cements

Objectives The aim of this study was to measure the degree of conversion (DC) of five dual-curing resin cements after different curing modes with a second- and a third-generation light-emitting diode (LED) curing unit. Additionally, irradiance of both light curing units was measured at increasing distances and through discs of two glass ceramics for computer-aided design/manufacturing (CAD/CAM). Materials and methods Irradiance and spectra of the Elipar FreeLight 2 (Standard Mode (SM)) and of the VALO light curing unit (High Power Mode (HPM) and Xtra Power Mode (XPM)) were measured with a MARC radiometer. Irradiance was measured at increasing distances (control) and through discs (1.5 to 6 mm thickness) of IPS Empress CAD and IPS e.max CAD. DC of Panavia F2.0, RelyX Unicem 2 Automix, SpeedCEM, BisCem, and BeautiCem SA was measured with an attenuated total reflectance–Fourier transform infrared spectrometer when self-cured (negative control) or light cured in SM for 40 s, HPM for 32 s, or XPM for 18 s. Light curing was performed directly (positive control) or through discs of either 1.5- or 3-mm thickness of IPS Empress CAD or IPS e.max CAD. DC was analysed with Kruskal–Wallis tests followed by pairwise Wilcoxon rank sum tests (α = 0.05). Results Maximum irradiances were 1,545 mW/cm2 (SM), 2,179 mW/cm2 (HPM), and 4,156 mW/cm2 (XPM), and all irradiances decreased by >80 % through discs of 1.5 mm, ≥95 % through 3 mm, and up to >99 % through 6 mm. Generally, self-curing resulted in the lowest DC. For some cements, direct light curing did not result in higher DC compared to when light cured through ceramic discs. For other cements, light curing through ceramic discs of 3 mm generally reduced DC. Conclusions Light curing was favourable for dual-curing cements. Some cements were more susceptible to variations in curing mode than others. Clinical relevance When light curing a given cement, the higher irradiances of the third-generation LED curing unit resulted in similar DC compared to the second-generation one, though at shorter light curing times.

Everolimus dual effects of an area vasculosa angiogenesis and lymphangiogenesis

Recently approved as treatment for astrocytoma, kidney and pancreatic cancer, everolimus acts on tumor cells by inhibiting tumor cell growth and proliferation, as well as by inhibition of angiogenic activity by both direct effects on vascular cell proliferation and indirect effects on growth factor production. The effects of everolimus on early stages of normal vasculogenesis, angiogenesis and lymphangiogenesis are not yet available. We found increased development of intravascular pillars by using area vasculosa of the chick chorioallantoic membrane treated with everolimus. An active lymphangiogenic response was highlighted by the expression of Prospero homeobox protein 1 (Prox1) and podoplanin, together with vascular endothelial growth factor receptor C (Vegf-C) and vascular endothelial growth factor receptor 3 (Vegfr-3) expression on day 4 in the treated group. These findings suggest a potential role of everolimus in the activation of lymphangiogenesis.

Variation of a test's sensitivity and specificity with disease prevalence

BACKGROUND Anecdotal evidence suggests that the sensitivity and specificity of a diagnostic test may vary with disease prevalence. Our objective was to investigate the associations between disease prevalence and test sensitivity and specificity using studies of diagnostic accuracy. METHODS We used data from 23 meta-analyses, each of which included 10-39 studies (416 total). The median prevalence per review ranged from 1% to 77%. We evaluated the effects of prevalence on sensitivity and specificity using a bivariate random-effects model for each meta-analysis, with prevalence as a covariate. We estimated the overall effect of prevalence by pooling the effects using the inverse variance method. RESULTS Within a given review, a change in prevalence from the lowest to highest value resulted in a corresponding change in sensitivity or specificity from 0 to 40 percentage points. This effect was statistically significant (p < 0.05) for either sensitivity or specificity in 8 meta-analyses (35%). Overall, specificity tended to be lower with higher disease prevalence; there was no such systematic effect for sensitivity. INTERPRETATION The sensitivity and specificity of a test often vary with disease prevalence; this effect is likely to be the result of mechanisms, such as patient spectrum, that affect prevalence, sensitivity and specificity. Because it may be difficult to identify such mechanisms, clinicians should use prevalence as a guide when selecting studies that most closely match their situation.

Self-dual continuous processes

The important application of semi-static hedging in financial markets naturally leads to the notion of conditionally quasi self-dual processes which is, for continuous semimartingales, related to conditional symmetry properties of both their ordinary as well as their stochastic logarithms. We provide a structure result for continuous conditionally quasi self-dual processes. Our main result is to give a characterization of continuous Ocone martingales via a strong version of self-duality.

The (2 + 1)-d U (1) quantum link model masquerading as deconfined criticality

The (2 + 1)-d U(1) quantum link model is a gauge theory, amenable to quantum simulation, with a spontaneously broken SO(2) symmetry emerging at a quantum phase transition. Its low-energy physics is described by a (2 + 1)-d RP(1) effective field theory, perturbed by an SO(2) breaking operator, which prevents the interpretation of the emergent pseudo-Goldstone boson as a dual photon. At the quantum phase transition, the model mimics some features of deconfined quantum criticality, but remains linearly confining. Deconfinement only sets in at high temperature.

Expanding the cone location and magnitude index to include corneal thickness and posterior surface information for the detection of keratoconus

PURPOSE To extend the capabilities of the Cone Location and Magnitude Index algorithm to include a combination of topographic information from the anterior and posterior corneal surfaces and corneal thickness measurements to further improve our ability to correctly identify keratoconus using this new index: ConeLocationMagnitudeIndex_X. DESIGN Retrospective case-control study. METHODS Three independent data sets were analyzed: 1 development and 2 validation. The AnteriorCornealPower index was calculated to stratify the keratoconus data from mild to severe. The ConeLocationMagnitudeIndex algorithm was applied to all tomography data collected using a dual Scheimpflug-Placido-based tomographer. The ConeLocationMagnitudeIndex_X formula, resulting from analysis of the Development set, was used to determine the logistic regression model that best separates keratoconus from normal and was applied to all data sets to calculate PercentProbabilityKeratoconus_X. The sensitivity/specificity of PercentProbabilityKeratoconus_X was compared with the original PercentProbabilityKeratoconus, which only uses anterior axial data. RESULTS The AnteriorCornealPower severity distribution for the combined data sets are 136 mild, 12 moderate, and 7 severe. The logistic regression model generated for ConeLocationMagnitudeIndex_X produces complete separation for the Development set. Validation Set 1 has 1 false-negative and Validation Set 2 has 1 false-positive. The overall sensitivity/specificity results for the logistic model produced using the ConeLocationMagnitudeIndex_X algorithm are 99.4% and 99.6%, respectively. The overall sensitivity/specificity results for using the original ConeLocationMagnitudeIndex algorithm are 89.2% and 98.8%, respectively. CONCLUSIONS ConeLocationMagnitudeIndex_X provides a robust index that can detect the presence or absence of a keratoconic pattern in corneal tomography maps with improved sensitivity/specificity from the original anterior surface-only ConeLocationMagnitudeIndex algorithm.

Cutaneous lesions associated with dual infection caused by canine distemper virus and orthopoxvirus in a domestic cat.

BACKGROUND Within the context of an increased epidemiological pressure caused by canine distemper virus (CDV) in Switzerland together with a potential re-emergence of endemic pathogens such as orthopoxviruses (OPXV), dual infections are possible among susceptible species. OBJECTIVE To describe a case of concurrent CDV and OPXV infection in a cat. ANIMAL A 5-year-old, neutered male cat was presented with erythema, crusts and ulcerations around the left eye. High-grade pruritus and a severe conjunctivitis were also present. METHODS Formalin-fixed skin biopsy samples were obtained from lesional skin. Histopathology, CDV immunohistochemistry and CDV and OPXV RT-PCR were performed. RESULTS Histopathological examination showed severe epidermal necrosis extending to the follicular walls and a dermal infiltration, predominantly eosinophilic. Intranuclear and intracytoplasmic eosinophilic inclusion bodies were visible in the wall of affected hair follicles, with occasional formation of syncytia. The RT-PCR revealed the contextual presence of both CDV and OPXV. Scattered cells stained positive for CDV by immunohistochemistry. CONCLUSION AND DISCUSSION Dual infections with CDV and OPXV, although rare, may occur and represent additional differential diagnoses for ulcerative skin lesions in cats.

HLA-B⁎27 subtype specificity determines targeting and viral evolution of a hepatitis C virus-specific CD8+ T cell epitope

Background & Aims: HLA-B⁄27 is associated with spontaneous HCV genotype 1 clearance. HLA-B⁄27-restricted CD8+ T cells target three NS5B epitopes. Two of these epitopes are dominantly targeted in the majority of HLA-B⁄27+ patients. In chronic infection, viral escape occurs consistently in these two epitopes. The third epitope (NS5B2820) was dominantly targeted in an acutely infected patient. This was in contrast, however, to the lack of recognition and viral escape in the large majority of HLA-B⁄27+ patients. Here, we set out to determine the host factors contributing to selective targeting of this epitope. Methods: Four-digit HLA class I typing and viral sequence analyses were performed in 78 HLA-B⁄27+ patients with chronic HCV genotype 1 infection. CD8+ T cell analyses were performed in a subset of patients. In addition, HLA/peptide affinity was compared for HLA-B⁄27:02 and 05. Results: The NS5B2820 epitope is only restricted by the HLA-B⁄27 subtype HLA-B⁄27:02 (that is frequent in Mediterranean populations), but not by the prototype HLA-B⁄27 subtype B⁄27:05. Indeed, the epitope is very dominant in HLA-B⁄27:02+ patients and is associated with viral escape mutations at the anchor position for HLA-binding in 12 out of 13 HLA-B⁄27:02+ chronically infected patients. Conclusions: The NS5B2820 epitope is immunodominant in the context of HLA-B⁄27:02, but is not restricted by other HLA-B⁄27 subtypes. This finding suggests an important role of HLA subtypes in the restriction of HCV-specific CD8+ responses. With minor HLA subtypes covering up to 39% of specific populations, these findings may have important implications for the selection of epitopes for global vaccines.

Dual-Domain Image Denoising

Image denoising methods have been implemented in both spatial and transform domains. Each domain has its advantages and shortcomings, which can be complemented by each other. State-of-the-art methods like block-matching 3D filtering (BM3D) therefore combine both domains. However, implementation of such methods is not trivial. We offer a hybrid method that is surprisingly easy to implement and yet rivals BM3D in quality.

FoxM1B regulates NEDD4-1 expression, leading to cellular transformation and full malignant phenotype in immortalized human astrocytes.

Our recent studies have shown that the FoxM1B transcription factor is overexpressed in human glioma tissues and that the level of its expression correlates directly with glioma grade. However, whether FoxM1B plays a role in the early development of glioma (i.e., in transformation) is unknown. In this study, we found that the FoxM1B molecule causes cellular transformation and tumor formation in normal human astrocytes (NHA) immortalized by p53 and pRB inhibition. Moreover, brain tumors that arose from intracranial injection of FoxM1B-expressing immortalized NHAs displayed glioblastoma multiforme (GBM) phenotypes, suggesting that FoxM1B overexpression in immortalized NHAs not only transforms the cells but also leads to GBM formation. Mechanistically, our results showed that overexpression of FoxM1B upregulated NEDD4-1, an E3 ligase that mediates the degradation and downregulation of phosphatase and tensin homologue (PTEN) in multiple cell lines. Decreased PTEN in turn resulted in the hyperactivation of Akt, which led to phosphorylation and cytoplasmic retention of FoxO3a. Blocking Akt activation with phosphoinositide 3-kinase/Akt inhibitors inhibited the FoxM1B-induced transformation of immortalized NHAs. Furthermore, overexpression of FoxM1B in immortalized NHAs increased the expression of survivin, cyclin D1, and cyclin E, which are important molecules for tumor growth. Collectively, these results indicate that overexpression of FoxM1B, in cooperation with p53 and pRB inhibition in NHA cells, promotes astrocyte transformation and GBM formation through multiple mechanisms.

Evolutionarily conserved role of calcineurin in phosphodegron-dependent degradation of phosphodiesterase 4D.

Calcineurin is a widely expressed and highly conserved Ser/Thr phosphatase. Calcineurin is inhibited by the immunosuppressant drug cyclosporine A (CsA) or tacrolimus (FK506). The critical role of CsA/FK506 as an immunosuppressant following transplantation surgery provides a strong incentive to understand the phosphatase calcineurin. Here we uncover a novel regulatory pathway for cyclic AMP (cAMP) signaling by the phosphatase calcineurin which is also evolutionarily conserved in Caenorhabditis elegans. We found that calcineurin binds directly to and inhibits the proteosomal degradation of cAMP-hydrolyzing phosphodiesterase 4D (PDE4D). We show that ubiquitin conjugation and proteosomal degradation of PDE4D are controlled by a cullin 1-containing E(3) ubiquitin ligase complex upon dual phosphorylation by casein kinase 1 (CK1) and glycogen synthase kinase 3beta (GSK3beta) in a phosphodegron motif. Our findings identify a novel signaling process governing G-protein-coupled cAMP signal transduction-opposing actions of the phosphatase calcineurin and the CK1/GSK3beta protein kinases on the phosphodegron-dependent degradation of PDE4D. This novel signaling system also provides unique functional insights into the complications elicited by CsA in transplant patients.

Interlinked dual-time feedback loops can enhance robustness to stochasticity and persistence of memory.

Multiple interlinked positive feedback loops shape the stimulus responses of various biochemical systems, such as the cell cycle or intracellular Ca2+ release. Recent studies with simplified models have identified two advantages of coupling fast and slow feedback loops. This dual-time structure enables a fast response while enhancing resistances of responses and bistability to stimulus noise. We now find that (1) the dual-time structure similarly confers resistance to internal noise due to molecule number fluctuations, and (2) model variants with altered coupling, which better represent some specific biochemical systems, share all the above advantages. We also develop a similar bistable model with coupling of a fast autoactivation loop to a slow loop. This model's topology was suggested by positive feedback proposed to play a role in long-term synaptic potentiation (LTP). The advantages of fast response and noise resistance are also present in this autoactivation model. Empirically, LTP develops resistance to reversal over approximately 1h . The model suggests this resistance may result from increased amounts of synaptic kinases involved in positive feedback.